Are you sure there is any special post-processing to achieve that? It looks like very basic processing to me...perhaps just a bit of desaturation. I think the lighting setup takes care of the rest.
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jrista♦Aug 13 '10 at 6:51

I think you can do this by toning the image towards cold tones (in GIMP it's Colors/Color Balance: you tone down reds and enhance blues, Photoshop should be similar) and then decreasing saturation (Hue/saturation adjustment should be somewhere there as well).

I think its just desaturated, as you can still see some pink in the puppies skin around his nose. I generally agree though, just over-sharpened and desaturated, not much in the way of processing.
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jrista♦Aug 13 '10 at 9:20